Arrangement and method adapted to control high-frequency circuits



Sept. 9, 1930; QSNQS 1,775,210

ARRANGEMENT AND METHOD ADAPTED T0 CONTROL HIGH FREQUENCY CIRCUITS FiledDec. 1, 925

INVENTOR MENDEL OSNOS TORNEY Patented Sept. 9, 1930 UNETED STATES PATENTOFFICE MENDEL OSNOS, or BERLIN, GERMANY, ASSIGNOR TO'GESELLSCHAFTrtrn'nnAnrLosn TELEGRAPHIE M. 3. IL, or BERLIN, GERMANY, A CORPORATIONor GERMANY ARRANGEMENT AN D METHOD ADAPTED T0 CONTROL HIGH-FREQUENCYCIRCUITS Application filed December 1, 1925, Serial No. 72,458, and inGermany December 4, 1924.,

It is wellknown that high-frequency circuits may be controlled by meansof the variation of an ohmic resistance or an impedance, the changes inimpedance being accomplished by variations of the magnetic properties ofthe controlling device, for instance, by the aid of the super-positionof an auxiliary field.

However, in a great number of cases this is attended with a certaindifliculty because the controlling currents, in order to efi'ectivelyinfluence the permeability, must be chosen comparatively large. If akind of construction is to be resorted to in which the controllingcurrent is made to flow through a coil consisting of a great number ofturns, there frequently arises another difficulty. The controller coilis often damaged by the heating of the iron body of the controllerdevice.

It may be desirable to use for the control a device of the typedisclosed in my co-pending application Serial No. 64,245, filed October22, 1925. This consists of a conductor preferably made of copper whichis surrounded by iron, and which consequently, may involve considerableself-inductance as well as a high ohmic resistance on account of thehysteresis and eddy-current losses set up in the iron.

By suflicient saturation in the iron by the aid of a superposedcontrolling field, it is possible to greatly vary both the inductive aswell as the ohmic resistance of the device. If the same conductor thatcarries the high frequency current to be modulated is to be used as theconductor for the controlling current, it is necessary for thecontrolling currents in order to be effective to be of approximately thesame order of magnitude as the high frequency currents. They will haveto be relatively large, as a result of which the serious diflicultyabove referred to is encountered. But if a separate controlling coilconveniently disposed upon the iron of the apparatus is used for thecontrolling currents, the other difiiculty above mentioned will ariseand the coils become damaged by heating.

According to this invention the difliculties referred to are obviated byusing a controlling impedance that is not inserted directly in thecircuit to be controlled, but is in inductive coupling relationshiptherewith through an iron-cored transformer whose coupling capacity isvariable within wide limits by the aid of an additional excitation.Hence, by changing the coupling it is possible to detract resistancefrom the circuit to be controlled, or add resistance thereto.

The coil carrying the controlling current is Wound upon the couplingtransformer and is iidependent of the controlling resistance use 1 Oneform of construction of the idea underlying the invention is illustratedin the accompanying drawing in which 2- Fig. 1 shows my arrangement, and

Fig. 2 is a modification. Referring first to Fig. 1v of the drawings, Iis the circuit to be controlled, a. b the controlling impedance of thekind as above described, consisting of a conductor a and an iron coat orsheath 7). d d are the coupling coils comprising a core of iron 6conveniently closed upon itself, while f is the controller windingwrapped upon the same core. In order that no voltages of the highfrequency to be modulated may be induced in the winding f, itis a goodplan, as shown in Fig. 2, to arrange the high frequency winding d andthe controlling winding 7 upon two iron cores 6,, 6 preferably closedupon themselves in a way so as to act differentially with relation toone another.

Having thus described my invention, what I claim is 1. In combination, ahigh frequency circuit and controlling impedance coupled therewith, saidcoupling means including an iron core transformer, said impedancecomprising a copper conductor surrounded by a plurality of thin magneticdisks for reducing hysteresis and eddy current losses, and a controllingcircuit coupled with said high frequency circuit and said impedancethrough said iron core transformer, said controlling circuit beingindependent of said high frequency circuit and said controllingimpedance, said controlling circuit being adapted to control the effectof said impedance upon said high frequency circuit by varying the degreeof coupling of said controlling circuit with said high frequencycircuit.

2. In combination, a high frequency circuit and controlling impedancecomprising a copper body surrounded by a magnetic layer, an iron coretransformer for inductively coupling said high frequency circuit andsaid impedance, means for varying the saturationof said magnetic layerby varying the -degree ofcoup-ling of said impedance with said highfrequency circuit, a controlling circuit coupled with both said highfrequency circuit and said impedance for controlling the eifect of saidimpedance upon 5 said high frequency circuit by varying the degree ofcoupling of said impedance with said high frequency circuit, and meansprovided by said iron core transformer for Wind ing said high frequencycircuit upon said so transformer in. a differential relationship wherebythe effects of said high frequency are avoided in said controllingcircuit.

3. In combination, a high frequency circuit, a controlling impedancecomprising a copper conductor surrounded by a plurality of thin magneticdisks, an iron core transformer, means for coupling said high frequencycircuit and'said controlling imped ance, a controlling circuitmagnetically asso sociated with both said high frequency circuit andsaid controlling impedance for controlling the effect of said impedanceupon said'high frequency circuit by controlling the degree of couplingbetween said impedance and said high frequency circuit, and meansprovided by splitting the high frequency portion of said transformerwindings into two differentially wound'portions for causing the voltagesproduced by the high fre 40 quency currents in the said windings to actdifferentially one upon the'other and avoiding the effects of the 'highfrequency in the said controlling circuit.

MENDEL osNos.

